To introduce this standard, I want to quote extensively from Paul's words in Romans 14. I believe the entire chapter deals directly with this aspect of charity (that it "doth not behave itself unseemly"), but I am going to excerpt specific verses simply for brevity's sake. (Understanding that this still will be a long post.)
1 Him that is weak in the faith receive ye, but not to doubtful disputations.
To me, this says that we should welcome those whose faith is weak, but not in order to engage in "doubtful disputations". This phrase (doubtful disputations) might mean arguments that are centered on the weak one's doubts, BUT another alternative meaning that I believe fits the chapter better is "unsettled in opinion or belief; undecided". This can mean that we should not disupte with those whose faith is weak over issues/doctrines/ etc. that are unsettled or undecided. Again, I believe this fits the example that Paul gives in the following verses very well.
2 For one believeth that he may eat all things: another, who is weak, eateth herbs.
This divides the people being described into two sides - those who will eat anything (including meat) and those who eat herbs (and not meat).
3 Let not him that eateth despise him that eateth not; and let not him which eateth not judge him that eateth: for God hath received him.
These two groups are working from different "cultural/religious standards" - and Paul's initial message to each group is to not despise the other simply because of those differences.
5 One man esteemeth one day above another: another esteemeth every day alike.
Let every man be fully persuaded in his own mind.
Here Paul recognizes that people view different things differently (probably in reference to the Sabbath and religious holy days in this verse), and he asks everyone to reach a conclusion individually that can be that person's "full" conclusion. In other words, he asks that each of us strive to understand our own situation and what God would have us do (even though he also says that we "see through a glass, darkly"), while accepting that others will reach different understanding for themselves.
6 He that regardeth the day, regardeth it unto the Lord; and he that regardeth not the day, to the Lord he doth not regard it. He that eateth, eateth to the Lord, for he giveth God thanks; and he that eateth not, to the Lord he eateth not, and giveth God thanks.
In this verse, Paul highlights a critical point - that those who disagree even with regard to things that they view as highly important (like the Sabbath and what is appropriate to eat) ALL do what they do "to the Lord" (as an expression of faith to God).
10 But why dost thou judge thy brother? or why dost thou set at nought thy brother? for we shall all stand before the judgment seat of Christ. 11 For it is written, As I live, saith the Lord, every knee shall bow to me, and every tongue shall confess to God. 12 So then every one of us shall give account of himself to God.
This is an important point:
We have to account for our own actions, so why do we worry about accounting for others' actions?
In that spirit, Paul adds:
13 Let us not therefore judge one another any more: but judge this rather, that no man put a stumblingblock or an occasion to fall in his brother’s way. 14 I know, and am persuaded by the Lord Jesus, that there is nothing unclean of itself: but to him that esteemeth any thing to be unclean, to him it is unclean. 15 But if thy brother be grieved with thy meat, now walkest thou not charitably. Destroy not him with thy meat, for whom Christ died.
There is a famous saying,
"When in Rome, do as the Romans do."
This saying was taken from this chapter (in Romans), and, while I am not saying that we should participate in everything that is acceptable in other cultures, I am saying that charity includes being able to recognize which cultural aspects that others follow are fine to follow while among them and not use as the source for "doubtful disputations".
My father used to say to us, when we asked about whether or not we could do something,
"Is it critical to your eternal salvation?"
He did this NOT to limit what we could do by viewing everything as critical, but rather he did this to help us see that there are MANY things we can do that really are NOT critical to our eternal salvation. I believe he was teaching us to be charitable in not behaving ourselves unseemly - by helping us realize that we don't need to enclose ourselves so tightly in proscriptive standards that we end up not being able to socialize with those whose standards are not as proscriptive (and vice-versa) - or whose standards are proscriptive in different ways.
21 It is good neither to eat flesh, nor to drink wine, nor any thing whereby thy brother stumbleth, or is offended, or is made weak.
In summary, Paul restates his point - and he does so primarily to those for whom "eat(ing) flesh" and "drink(ing) wine" are not an offense and do not make weak. He is saying, in essence, that those who can handle it should not partake among those who can't. In our modern Mormon vernacular, he is saying that those who are strong should adapt their behavior to accommodate "the weakest of the weak who are or can be called saints".
I would add only this, to bring the entire discussion full circle:
Not only should we adapt our "physical actions" to accommodate the weak (by not eating and drinking that which would offend or weaken them or cause them to stumble), but we also should adapt our "verbal actions" to accommodate them (by not participating in doubtful disputations with them over standards that are "unsettled" and open to interpretation).
The responsibility is NOT on the weak; it is on the strong. If you think, for example, that the Word of Wisdom is trivial, inconsequential and not all that important, prove your strength by being charitable and abstaining for the sake of the weak - those for whom abstaining really is critical to their eternal salvation.